I'm trying to set up dual monitors and the desktop it's self has 3 DVI ports, though only one works. The desktop has a NVIDIA GeForce GTX 645 external graphics card and tech support told me that as long as it was installed I could not set up dual DVI display. I would describe myself as moderately computer literate, but am unsure as how to go about getting dual monitors on my setup. Any and all suggestions would be great, but my budget is limited so I can't spend a fortune on setting this up. Thanks!